I learned something yesterday, and wanted to share it for others' edification. And correction for me if needed.

I acquired some used Tyvek envelopes marked with green triangles and diamonds for First Class Mail. For some weeks, I have been reusing them for PBS. I drew lines with a Sharpie through the green, and made sure all postage and addresses were off or covered up.

Yesterday, one of these came back to me as postage due (4 days after I mailed it!! Not sure if if was one I mailed there, or in a neighboring town). It had a sticker saying something about First Class not able to be downgraded, and suggesting Priority at $4.60. I took it back to my PO. Folks there consulted with each other, and agreed that First Class envelopes can only be reused for First Class or "higher", not "downgraded".

Not sure why anybody cares. Only reason I can think of is to remove a very minor chance of confusion. But I don't want packages to be delayed, so I guess I'll stop that. I'll try turning the envelopes inside out, or cutting one side open.

Has anyone else run into this? I don't recall seeing it mentioned on the forums.

I only know about not reusing priority boxes and envelopes, never heard about the first class envelopes but I guess I can see where that would make sense if they have the rule for the priority to do the same for first class

If any part of any restriction is showing on an envelope or box, the PO employees must treat it as tho it were containing that restrictive item. Example if the box contains a symbol or restriction due to a specific type of liquid, that required a temperature limitation, they have to treat it as if that is in the box, even tho you may X it out. If you don't completely obliterate it, they have to abide by it.

My guess then on the first class envelopes, is that unless you tape over those green triangles and diamonds, there is the possiblity that someone might glance at the envelope and think it is a 1st class still, even tho you have MM on it. It's also possible that their machinery is 'sighted' to see those triangles & diamonds thereby eliminating a person having to pick them out as 1st class, the machine clicks a door and the envelope goes down a different shoot?

I wouldn't think they should fall in the same class as the priority envelopes that are provided free, since someone paid for the 1st class, it has to be a recognition thing, I would think. I don't know what else it would be.

I've never run into that problem but given that you have, the easiest method is to turn the envelopes inside out. If these are not USPS issued envelopes, there should not be an issue with turning purchased envelopes inside out to reuse.

Susan, that seems the best idea. The USPS cannot regulate when and how you use envelopes not provided for free by us. However, as stated by Sherry, if the markings are showing at all, it could create confusion as to what service you really wanted and which was the reused purpose. As the USPS would choose not to slow the mail down, it might end up postage due for Priority at the other end.

I've used those first class tyvek envelopes many times in mailing! The only requirement my post office imposes is that you black out any word of "first class" on them. I've never had one returned for additional first class postage either!

If the triangles say "First Class" on them as many due then if you want to use the envelopes inside out as suggested. The plain triangles should be OK as long as nothing is marked "First Class" but if was me I wouldn't take the chance.

Starting in May the surface classification of mail was eliminated on a world wide basis, by all postal services. All things international now go by air and the classifications are the same as domestic, i.e. First Class, Priority, Express, etc.

Prior to that we marked things either Air Mail or Surface, or a variation of those terms, except for letters which have gone by air only for years and years. I have seen cases where clerks have accepted flats with the green First Class border and have them returned from the country of destination because thier mail classifications had different terminology and they wouldn't recognize First Class as a service they offered. Canada could get fanatical about it. We were trained not to accept them for international but like some other things some clerks soon forgot it or didn't have to deal with it.